Treating fatty acid nitriles to improve the odor thereof



Patented Apr. 10, 1951 i UNITED STATES PATENT OFFICE 72,548,363 TREATING FATTY ACID. NITRILES To IMPROVE THE OD James Harwood,

Brow, Chicago,

No. Draw OR, THEREOF Western Springsand Paul Du I 111., assignors to Armour and Company, Chicago, Illa corporation of Illinois Application December 1 0, 194,8, Serial- 6 ,16 4.

4 Claims. (Cl. 202*? This invention relates to a process for treating'high molecular weight fatty acid nitriles to remove objectionable odors.

"The high molecular weight fatty acid nitriles having 12 or more carbon atoms, which are commercially produced by'the reaction of fatty acids and ammonia; are known to possess a char- Although it has heretofore been suggested that the odor of the fatty acid nitriles may be somewhat improved by washing with certain many of the above uses.

\ We have now discovered that anitrile product can be prepared which has none of the usual nitrile odor by subjecting the odoriferous nitriles to treatment with phosphoric acid so as to form a precipitate. In carrying out our process we contact the odoriferious nitriles' with phosphoric acid in any convenient way; We may simply place the nitriles in a vat or tanlg off to physically separate them from the precipitate layerwhich isdiscarded.

Not only does our discoverey make Our process is applicable to all the high molecular weight fatty acid nitriles containing 12 or more carbon atoms. Examples are lauric acid nitrile, palmitonitrile, oleonitrile and stea- The ronitrile. from which by weight. I v v o ev c osephoric acid than the 5% above referred to, may, be used, but w hout sub antial additio al filling the mixture.

spe ifie xam es or; ha ract qe frw il -Wen:

ime are; ven; as fol ws:

Example 1 100 parts of crude tallow nitriles were treated with; 5 partsof phosphoricacida The mixture was-stirred-and heated at --C;

Example 2 e parts of crude coconuttnitriles weretreated with5 partsofr85% phosphoricgaqidr and th mix, ture was heated at 60-C. to 70 C, andstirred for hou mg mtrile tionable odor.

3 Eatample 3 100 parts of crude cottonseed nitriles were treated with parts of 85% phosphoric acid.

The mixture was stirred at 25 to 30 C. for 6 hours. The black sludge which formed was separated and the material was washed with water as in Examples 1 and 2. The product was free of any objectionable odor.

Example 4 To 100 parts of crude tallow nitrile were added 5 parts of 85% phosphoric acid. The resulting mixture was distilled at a pressure of 1 mm., the temperature reaching a maximum parts of distilled nitrile were obtained which were found to be substantially free of objectionable odor.

In any process which involves improving the odor of a substance, the eiiectiveness of the process must be tested by smelling the final product, and, since the sensitivity of the olfactory lobes is quite apt to vary from person to person, we have devised an additional test for the effectiveness of our process. This test, which is described and explained below, is much more sensitive than merely smelling the final nitrile product and involves smelling the concentrated odor producing substance after it has been removed from the nitrile.

When, in our process, odoriferous nitriles are treated with phosphoric acid, the latter combines with the odor-producing substance to form a complex which precipitates and is separated as a sludge. In our additional test, we then hydrolyze or split this complex by treating with NaOH. This frees the odor-forming part of the complex, and the characteristic undesirable odor immediately becomes noticeable. Thus, if any odor-producing is removed from the nitrile, its presence in the sludge can readily be detected.

The utility of this additional test may be illustrated by the following examples:

Example 5 The black sludge (phosphoric acid) layer, which was separated and removed in Example 1, was treated with NaOI-I. The typpical disagreeable odor usually associated with nitriles immediately became noticeable.

' The nitrile layer, which was separated in Example l, was once again treated with 5% of 85% phosphoric acid. The mixture was stirred and heated at 90 C. for 6 hours. The phosphoric acid layer was then treated with NaOl-I. No typical disagreeable odor was given off, thus indicating that the first treatment with phosphoric acid had removed the odor-producing substance completely.

Example 6 150 g. tallow nitriles were treated with 5% of 5%. HCl. The mixture was stirred and heated at 90 C. for 6 hours. The HCl layer was separated and treated with NaOH. A slight odor was given ofi.

The nitrile layer was washed to remove HCl and was then treated with 5% of 85% phosphoric acid. The mixture was stirred and heated at 90 C. for 6 hours. The phosphoric acid layer was then separated and treated with NaOH. A typical disagreeable odor was immediately given off, indicating that all the odor-producing substance of 160 C. 95

4 had not been removed from the nitriles HCl treatment.

by the Example 7 150 g. of tallow nitriles were treated with 5% of 5% H2804. The mixture was stirred and heated at 90 C. for 6 hours. The H2804 layer was treated with NaOH. A slight odor was given The nitrile layer was washed to remove H2304 and was then treated with 5% of phosphoric acid. The mixture was stirred and heated at C. for 6 hours. The phosphoric acid layer was then separated and treated with NaOH. A typical disagreeable odor was immediately given off, thus indicating that all the odor-producing substance had not been removed from the nitriles by the H2804 treatment.

The foregoing detailed description and examples have been given for explanation only and it is to be expected that the methods and procedures above given may be widely varied, all within the spirit of our invention.

This is a continuation in part of our application Serial No. 731,862, filed March 1, 1947, now abandoned.

We claim:

1. A process for treating fatty acid nitriles containing at least 12 carbon atoms to remove objectionable odor therefrom, comprising admixing with said nitriles phosphoric acid, heating the mixture to between 25 and C. for a period of from 2 to 6 hours, and separating from said nitriles a precipitate formed through the action of said mineral acid.

2. A process for treating fatty acid nitriles con taining at least 12 carbon atoms to remove objectionable odor, comprising admixing with said nitriles phosphoric acid, heating the mixture to between 25 and 100 C. for a period of from 2 to 6 hours, permitting the resulting precipitate to form in a layer apart from the main body of said nitriles, and separating said layer from the remaining nitriles.'

3. In a process for the treatment of nitriles containing at least 12 carbon atoms to remove objectionable odor therefrom, the steps of contacting with said nitriles phosphoric acid in a proportion of about 5% of the nitriles present, heating the mixture to between 25 and 100 C. for a period of from 2 to 6 hours, and distilling 'to separate said nitriles from phosphoric acid and the product formed as a result of said c ntact.

4. In a process for the treatment of nitriles containing at least 12 carbon atoms to remove objectionable odor therefrom, the step of distilling said nitriles in the presence of phosphoric acid.

JAMES HARWOOD. PAUL DU BROW.

REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 2,175,305 Jacobson Oct. 10, 1939 2,177,619 Nicodemus Oct. 24, 1939 2,247,255 Senkus June 24, 1941 2,267,269 Cheetham et al Dec. 27, 1941 2,361,367 Davis et al. Oct. 31, 1944 2,369,061 Loder et al Feb. 6, 1945 

1. A PROCESS FOR TREATING FATTY ACID NITRILES CONTAINING AT LEAST 12 CARBON ATOMS TO REMOVE OBJECTIONABLE ODOR THEREFROM, COMPRISING ADMIXING WITH SAID NITRILES PHOSPHORIC ACID, HEATING THE MIXTURE TO BETWEEN 25* AND 100* C. FOR A PERIOD OF FROM 2 TO 6 HOURS, SEPARATING FROM SAID NITRILES A PRECIPITATE FORMED THROUGH THE ACTION OF SAID MINERAL ACID. 